Embodiments described herein relate generally to a sleeper for use on tractor-trailers and a method of operation of such a sleeper. More specifically, embodiments described herein relate to a sleeper for a tractor-trailer having an enclosed volume that is adjustable and a method of operating such a sleeper.
Air drag on a tractor-trailer reduces the fuel efficiency of the vehicle. One area where significant drag is created is at a gap located between the tractor and the trailer. This gap is typically 36 to 48 inches, depending on the vehicle and depending on the amount of loading on the trailer. The larger the gap, the more air that is trapped in the gap, and more drag is created on the vehicle.
To counteract the air turbulence effects on fuel efficiency, air deflectors are attached to the vehicle. The air deflectors may cause air to stream over the gap in a more controlled, less turbulent manner. Air deflectors may be heavy and costly, and may be installed in a fixed position. Changes in the air deflector configuration may be performed manually, which generally requires the use of hand tools. Fixed air deflectors offer limited improvements to air resistance because they do not close the entire gap. The fixed air deflectors may require a minimum gap measurement that exceeds the turning radius of the semi-trailer in relation to the tractor cab.
During travel of the vehicle, and particularly when negotiating a curved path, there is variation in the gap between the tractor cab and the trailer. To reduce air drag, the gap between the tractor and the trailer should be minimized under all travel conditions. However, if the fixed deflectors are extended too far and the gap is too small, the corners of the semi-trailer may strike and possibly encroach into a rear wall of the cab of the tractor when the vehicle is negotiating a curved path. Accordingly, fixed deflectors may not minimize air drag under all travel conditions.
It is known for tractor-trailers to be provided with enclosed compartments situated behind the driver's seat and accessible from the truck cab. These enclosed compartments are called sleepers. Sleepers may include one or more bunks, tables, chairs, storage closets and other furniture and amenities. The greater the length of the sleeper, the more room that is provided for the driver.
Length of the sleeper is dictated by the swing clearance area. However, the swing clearance area is occupied only when the tractor-trailer is in a turning configuration. When the tractor-trailer is in a substantially straight configuration, the swing clearance area may be unused and represent available free space.